asdf-games/node_modules/individual/one-version.js

'use strict';

var Individual = require('./index.js');

module.exports = OneVersion;

function OneVersion(moduleName, version, defaultValue) {
    var key = '__INDIVIDUAL_ONE_VERSION_' + moduleName;
    var enforceKey = key + '_ENFORCE_SINGLETON';

    var versionValue = Individual(enforceKey, version);

    if (versionValue !== version) {
        throw new Error('Can only have one copy of ' +
            moduleName + '.\n' +
            'You already have version ' + versionValue +
            ' installed.\n' +
            'This means you cannot install version ' + version);
    }

    return Individual(key, defaultValue);
}